Planar magnetic transducers use a flat, lightweight diaphragm suspended in a magnetic field rather than a cone attached to a voice coil. The diaphragm in a planar magnetic transducer includes a conductive circuit pattern that, when energized, creates forces that move the diaphragm in the magnetic field to produce sound.
The structures encountered by a sound wave traveling from the diaphragm are obstacles that may negatively interfere with the sound wave. It is desirable for a sound wave as emitted from a diaphragm to encounter as little interference as possible as it travels from the diaphragm.